In the case of a conventional electrophotographic copying machine with an automatic document feeder, when the automatic feeder exchanges a document sheet, the operation of the scanning exposure optical system must be stopped to await the end of the automatic document feeding operation. In this case, the machine cannot start feeding copy paper until the end of the document paper feeding operation. As a result, it takes a long time for the machine to start its exposure operation. Therefore, it was difficult to realize an electrophotographic copying machine with high efficiency, especially in the case of a machine with a long copy paper feeding path. The reason is that if copy paper feeding is started after the end of a document feeder operation, the machine must await starting the exposure while the copy paper is being carried through the long path.